Clarify in docs that service files are not default installed (in

non-FHS).

Author: vmcj

doc/manual/install-judgehost.rst

@@ -178,7 +178,7 @@ added kernel options. On VM hosting providers such as Google Cloud or
 DigitalOcean, ``GRUB_CMDLINE_LINUX_DEFAULT`` may be overwritten
 by other files in ``/etc/default/grub.d/``.
 
-You have now configured the system to use cgroups. To create
+You have now configured the system to use cgroups. In a FHS install, to create
 the actual cgroups that DOMjudge will use, run::
 
   sudo systemctl enable create-cgroups --now
@@ -231,3 +231,6 @@ the judgedaemon.
 The judgedaemon can also be run as a service by running::
 
   sudo systemctl enable --now domjudge-judgehost
+
+This only works in a FHS install, if the judgehost has been installed with another
+option those `service` files have to manually copied to the right directory e.g. `/etc/systemd`.